L'installation de récifs artificiels est une solution classiquement proposée pour soutenir la petite pêche artisanale. C'est dans ce but qu'a été déployé dans la baie de Marseille le plus grand ensemble de récifs artificiels de Méditerranée. Ce système offre une opportunité de comprendre le fonctionnement trophique de ces structures par (1) la caractérisation des sources de matière organique (MO) (2) la détermination de leur utilisation par les consommateurs et (3) leur devenir au sein des réseaux trophiques. Ces questions ont été appréhendées à l'aide des isotopes stables du C et du N, de la caractérisation biochimique des sources de MO et de l'analyse des contenus stomacaux des poissons.Les sources de MO présentent des différences isotopiques et biochimiques, reflet de leurs fonctionnements différents. La MO particulaire en suspension est un pool variable influencé par les apports allochtones et soumis aux forçages climatiques. Elle est la source principale de MO sur les récifs artificiels. La production primaire benthique est très hétérogène et de qualité nutritionnelle faible. Elle contribue aux réseaux trophiques des récifs par le biais des détritus qu'elle produit. Enfin, la MOS est un pool détritique de faible qualité nutritionnelle. Les récifs artificiels ne modifient pas la structure et le fonctionnement des communautés naturelles de poissons et leur offrent des ressources alimentaires variées et importantes. L'ensemble des résultats acquis, via les isotopes stables et les contenus stomacaux, montrent que les récifs artificiels sont des producteurs de biomasse à partir des productions primaires locales. / Artificial reefs are a classical tool used to sustain small scale fisheries. In Marseille's Bay, the largest Mediterranean artificial reef system was deployed for this purpose. This system is a valuable opportunity to better understand the trophic functioning of artificial reefs, by (1) characterizing the organic matter (OM) sources, (2) determining how they are used by low trophic level consumers and (3) following their fate in the trophic networks. These issues were assessed by three approaches:C and N stable isotope ratios, biochemical composition of OM sources and fish stomach content.OM sources display isotopic and biochemical differences reflecting their functioning. Suspended POM is variable, under the influence of allochtonous inputs and controlled by climatic forcing. POM represents the main OM source of the artificial reef food webs. The benthic primary production has heterogeneous C and N stable isotope ratios and exhibits mainly high insoluble carbohydrates contents. Benthic primary production is integrated into trophic networks mainly in the form of detritus. Eventually the sediment organic matter is a detrital pool, characterized by a low variability and a poor nutritional quality.Artificial reefs do modify the organization and the functioning of natural fish communities, and provide diversified and important food resources. Stable isotope and stomach content analyses confirm the consumption of artificial reef invertebrates by small carnivorous fishes, preyed themselves by piscivorous predators. All these results confirm that artificial reefs can efficiently increase fish biomass by local production based on phytoplanktonic and local benthic OM sources.

Wir studieren optimale Handelsstrategien für einen risikoaversen Investor, der bis zu einem Zeitpunkt T ein Portfolio aufzulösen hat. Dieser kann auf einem traditionellen Markt (dem "Primärmarkt") handeln, wodurch er den Preis beeinflusst, und gleichzeitig Aufträge in einem Dark Pool erteilen. Dort ist die Liquidität nicht öffentlich bekannt, und es findet keine Preisfindung statt: Aufträge werden zum Preis des Primärmarkts abgewickelt. Deshalb haben sie keinen Preiseinfluss, die Ausführung ist aber unsicher; es muss zwischen den Preiseinflusskosten am Primärmarkt und den indirekten Kosten durch die Ausübungsunsicherheit im Dark Pool abgewogen werden. In einem zeitdiskreten Handelsmodell betrachten wir ein Kostenfunktional aus erwarteten Preiseinfluss- und Marktrisikokosten. Für linearen Preiseinfluss ist dieses linear-quadratisch und wir erhalten eine Rekursion für die optimale Handelsstrategie. Eine Position in einem einzelnen Wertpapier wird langsam am Primärmarkt abgebaut während der Rest im Dark Pool angeboten wird. Für eine Position in mehreren Wertpapieren ist dies wegen der Korrelation der Wertpapiere nicht optimal. Tritt im eindimensionalen Fall adverse Selektion auf, so wird die Attraktivität des Dark Pools verringert. In stetiger Zeit impliziert die Liquidationsbedingung eine Singularität der Wertfunktion am Endzeitpunkt T. Diese wird im linear-quadratischen Fall ohne adverse Selektion durch den Grenzwert einer Folge von Lösungen einer Matrix Differentialgleichung beschrieben. Mit Hilfe einer Matrixungleichung erhalten wir Schranken für diese Lösungen, die Existenz des Grenzwertes sowie ein Verifikationsargument mittels HJB Gleichung. Tritt adverse Selektion auf, ergeben umfangreiche heuristische Betrachtungen eine ungewöhnliche Struktur der Wertfunktion: Sie ist ein quadratisches "Quasi-Polynom", dessen Koeffizienten in nicht-trivialer Weise von der Position abhängen. Wir bestimmen dieses semi-explizit und führen ein Verifikationsargument durch. / We study optimal trading strategies of a risk-averse investor who has to liquidate a portfolio within a finite time horizon [0,T]. The investor has the option to trade at a traditional exchange (the "primary venue") which yields price impact and to place orders in a dark pool. The liquidity in dark pools is not openly displayed and dark pools do not contribute to the price formation process: orders are executed at the price of the primary venue. Hence, they have no price impact, but their execution is uncertain. The investor thus faces the trade-off between the price impact costs at the primary venue and the indirect costs resulting from the execution uncertainty in the dark pool. In a discrete-time market model we consider a cost functional which incorporates the expected price impact costs and market risk costs. For linear price impact, it is linear-quadratic and we obtain a recursion for the optimal trading strategy. For single asset liquidation, the investor trades out of her position at the primary venue, with the remainder being placed in the dark pool. For multi asset liquidation this is not optimal because of the correlation of the assets. In the presence of adverse selection in the one dimensional setting the dark pool is less attractive. In continuous time the liquidation constraint implies a singularity of the value function at the terminal time T. In the linear-quadratic case without adverse selection it is described by the limit of a sequence of solutions of a matrix differential equation. By means of a matrix inequality we obtain bounds of these solutions, the existence of the limit and a verification argument via HJB equation. In the presence of adverse selection the value function has an unusual structure, which we obtain via extensive heuristic considerations: it is a "quasi-polynomial" whose coefficients depend on the asset position in a non-trivial way. We characterize the value function semi-explicitly and carry out a verification argument.

Cette thèse étudie le rôle des brevets essentiels pour la coordination de l'innovation dans les standards des Nouvelles Technologies d'Information et de Communication (NTIC). Les firmes actives dans la standardisation ont réagi au défi de la marée de brevets essentiels en créant des mécanismes innovateurs de coordination, et notamment des consortia informels de standardisation et des pools de brevets. La thèse met en lumière le mécanisme d'appropriation original que représentent les brevets essentiels. Ce mécanisme peut cependant générer des incitations à recourir à des stratégies opportunistes. Les pools de brevets peuvent exacerber ces incitations, mais induisent également une augmentation du nombre de brevets déposés autour des standards technologiques. Les consortia informels ont un effet positif sur le nombre de brevets liés aux standards si les incitations à innover sont insuffisantes. L'effet des consortia est plus faible, voire négatif, si les incitations à innover sont excessives. Les brevets essentiels influencent le progrès technologique des standards, notamment en donnant lieu à un progrès plus continu, consistant dans de nombreuses mises à jour et évitant les remplacements de standards. / This thesis studies the role of essential patents for the coordination of innovation in ICT standards. The increasing number of essential patents around technological standards is an increasing challenge for standardizing firms. In response, these firms have developed innovative coordination mechanisms, and in particular patent pools and informal standards consortia. This thesis sheds light on the function of essential patents as a distinctive appropriation mechanism tailored to cumulative innovation. This mechanism can however induce incentives for opportunistic strategies, which can be even exacerbated by patent pools. Nevertheless, patent pools also lead to an increase in the number of patented technologies developed for technological standards. Informal consortia induce an increase in the number of standard-related patents when incentives to innovate are insufficient. When the incentives to innovate are excessive, the effect of consortia on the number of patents is weaker, or even negative. Essential patents have an incidence on the technological progress of standards. For instance, inclusion of essential patents induces a more continuous type of technological progress, consisting in many small standard updates, and avoiding discontinuous standard replacements.

published_or_final_version / Architecture / Master / Master of Architecture

Downslope flows and regions of enhanced cooling have important impacts on society and the environment. Parameterisation of these often subgrid-scale phenomena in numerical models requires a sound understanding of the underlying physical processes, which has been the overarching aim of this work. A numerical model has been used to characterise the development of a region of enhanced cooling in an idealised alpine valley with width and depth of order 10 and 1 km, respectively, under stable, decoupled, poorly-drained conditions. A focus of this work has been to remove the uncertainty surrounding the forcing mechanisms behind the development of regions of enhanced cooling. The average valley-atmosphere cooling has been found to be almost equally partitioned between radiative and dynamics effects. Complex interactions between the downslope flows and the region of enhanced cooling have been quantified for the first time. For example, relatively large variations in the downslope flows are generally restricted to the region of enhanced cooling and cannot solely be attributed to the analytical model of [McNider, 1982a]. These flow variations generally coincide with return flows above the downslope flows, where a thin region of unstable air occurs, as well as coinciding with elongated downslope flow structures. The impact of these interactions on the dispersion of passive pollutants has been investigated. For example, pollutants are generally trapped within the region of enhanced cooling. The concentration of pollutants within the region of enhanced cooling, emitted over the lower half of the slopes, increase as the emission source moves away from the ground-based inversion that expands from the bottom of the valley. The concentration of pollutants within the region of enhanced cooling is very similar when varying the location of the emission source over the top half of the valley slopes. This work includes a test of the effects of varying the horizontal numerical grid resolution on average valley-atmosphere temperature changes.

The influence of channel morphology and hydraulics on sediment transport within steep upland streams is investigated. Step-pools are the most common bedform in such streams. Bedload transport processes operating in a perennial step-pool stream in central England are established using magnetically-tagged particles and bedload pit samplers. Water-surface slope in two step-pool streams is monitored in detail. Water-surface slope measurements show that step-pool bedforms cause large spatial variations in flow depth during floods, and that the temporal variation of watersurface slope during a flood wave differs diametrically from the pattern found in lowgradient rivers that have little roughness. These results demonstrate that it is difficult to estimate the forces acting on the streambed in steep, rough streams and, therefore, conventionally established flow variables cannot be used to predict bedload transport . rates in step-pool channels. Particle tracing experiments are used to determine the control that step-pool morphology and flow hycfraulics have on particle displacements. Step-pool streams exhibit smaller particle travel distance per flood event than low-gradient rivers. This difference reflects the greater flow resistance and bed rugosity of step-pool streams. Bed morphology dictates flood particle displacement at step-pool bedform scale. It is shown that entrainment, pool export rates and transport distances of coarse sediment are dependent on downstream step dimensions, step permeability and pool form. Large variations in bedload transport rates at any given flow strength are associated with variable sediment supply, and particle tracing demonstrates that sediment availability is controlled at unit pool scale. Bedload consists of fine gravel moving over a stable bed surface at low discharges, while, at higher discharges, bedload coarsens, approaching the size of the pool bed material as the bed surface is partially mobilized. Step framework clasts are stable features of the streambed. Results from this study are incorporated into a descriptive model of discharge-related bedload transport phases in step-pool streams.

<p>How do food and agribusiness firms capture more profit in their value chain? How do innovative managers identify attractive adjacency and disintermediation opportunities? What options are available to a manager facing these questions and what economic incentives might motivate their strategic behavior? This study sought to address these timely questions, more effectively understand the strategic decisions facing food and agribusiness managers relative to value chain profit pools, and uncover some of the hidden dynamics between chain participants. Specifically, this study defines and quantifies the U.S. animal protein industry value chain across three species – hogs, cattle, and broiler chickens. The study found evidence to suggest that governance structure has strong ties to value generation and that intra-value chain dynamics impact price transmission between chain nodes. Further, this study creates a foundation for other researchers to continue examining agri-food value chain dynamics and its link to firm-level profitability, value capture, and long-term sustainability.</p>

La formation des sous-produits de chloration dans les piscines couvertes dépend de nombreux paramètres cinétiques et hydrauliques. Cette étude propose le développement d’un modèle de prédiction de la formation de certains sous-produits de chloration et de leur transfert dans l’air. La construction du modèle est basée sur le couplage de constantes cinétiques déterminées à l’échelle laboratoire avec des modèles hydrauliques caractérisant les écoulements dans le bassin. Afin de calibrer et de valider les modèles, un bassin expérimental à l’échelle 1/10ème a été mis en place. Par ailleurs, une méthode de mesure des concentrations des sous-produits de chloration dans l’eau et dans l’air par Membrane Inlet Mass Spectrometry a été évaluée. La représentativité et la reproductivité des expériences réalisées sur le bassin ont été étudiées. À l’échelle laboratoire, les constantes cinétiques de consommation du chlore, de formation du chloroforme et de formation du dichloroacétonitrile par chloration du Body Fluid Analogue utilisé pour mimer les apports organiques des baigneurs ont été déterminées. Le comportement hydraulique du bassin a été modélisé par une série de réacteurs idéaux. Cette modélisation a été validée par la réalisation d’expériences de traçage sur le bassin expérimental. Enfin, les constantes de transfert eau-air des sous-produits de chloration volatils ont été déterminées et comparées avec plusieurs modèles de la littérature. Les résultats obtenus montrent que les modèles permettent de prévoir de façon satisfaisante l’évolution des paramètres modélisés. Le bassin expérimental constitue également un outil prometteur pour la calibration de modèles et l’évaluation de solutions de traitement. / The formation of chlorination by-products in swimming pools depends on many kinetic and hydraulic parameters. This study presents the development of a predictive model for the formation of chlorination by-products as well as their water-to-air transfer. The model is based on the coupling of kinetic rates determined in batch with hydraulic models which describe the flows in the basin. A pilot pool unit has been built in order to collect experimental data for the calibration and validation of the models. Moreover an analytical method by Membrane Inlet Mass Spectrometry has been assessed. The representativeness and the reproducibility of experiments performed on the pilot pool unit have been described. Kinetic rates for chlorine consumption, chloroform formation and dichloroacetonitrile formation have been studied at lab scale, based on chlorination experiments of a Body Fluid Analogue, a mix of chemicals which reproduces human intakes in swimming pools. The hydraulic behavior of the basin has been modeled by a series of ideal reactors. The model has been validated by comparison with tracer-based experiments. Finally, water-to-air transfer rates have been determined and compared with models from the literature. The modeled parameters were satisfactorily modeled. Moreover the pilot pool unit has been demonstrated to be useful in calibrating models or in assessing treatment solutions.

Introdução: Os culicídeos (insetos da Ordem Diptera, Família Culicidae), vulgarmente conhecidos como pernilongos, são vetores de diversos agentes patogênicos de doenças humanas e animais e fator de incômodo à população em geral. Os recursos lançados com o objetivo de controlar as pragas urbanas utilizando compostos químicos devem ser feitos com o máximo de parcimônia a fim de se evitar a contaminação ambiental e dificultar o aparecimento de linhagens resistentes dos vetores e pragas urbanas aos biocidas empregados. Objetivos: Estabelecer índices de infestações de Culex quinquefasciatus baseados na contagem de insetos adultos e de suas formas imaturas, coletados em piscinões e propor instrumento para estimar o incômodo provocado pelas picadas na população do entorno. Materiais e Métodos: O período estabelecido de coleta de espécimes de mosquitos e dados provenientes foi de agosto de 2014 a maio de 2015. Foram escolhidos dois piscinões do Município de Santo André, o Piscinão do Bairro Bom Pastor e o Piscinão da Faculdade de Medicina (Valparaíso) para ser a área de estudo. Esta pesquisa propõe a construção de alguns índices de infestação da espécie em estudo baseado em duas vertentes: 1) Foi feito o diagnóstico por meio de contagem de pernilongos conduzida na área dos piscinões. Foram contados e identificados os exemplares adultos deste mosquito que foram coletados por meio de aspiração nos abrigos e a aspiração dentro de caixas de repouso que foram instaladas nas áreas dos piscinões e contagem de formas imaturas (larvas e pupas), recolhidas dos criadouros aquáticos dos piscinões. 2) Foram analisadas as reclamações provindas dos munícipes através do Sistema de Informação de Atendimento da Prefeitura Municipal, dentro de um raio limítrofe correspondente à área de influência de cada reservatório. Resultados: Foram coletados 1896 exemplares adultos na atividade de aspiração nos abrigos, 621 exemplares imaturos e 67 exemplares adultos aspirados das caixas de repouso. Identificados o sexo dos exemplares adultos e verificou-se a predominância de machos. A partir da amostragem efetuada com observância das variáveis naturais e antrópicas, e análise das reclamações, foram criados e aplicados três índices de infestação (Densidade de Imaturos por Litro, Índice de Mosquitos Aspirados por Minuto e Índice de Mosquitos Aspirados das Caixas de Repouso) e um índice de reclamações (Índice de Reclamações Correspondentes). Conclusões: Através da análise de aspectos sazonais, os índices mostram-se ferramentas importantes para as intervenções de controle desta praga. O método das caixas de repouso mostrou-se pouco produtivo se comparado aos outros índices. / Introduction: Culicids (Diptera: Culicidae) usually known as mosquitoes, are vectors of several animal and human diseases pathogenic agents and also are nuisance factors to general population. The features launched with the objective to control the urban pests using chemicals must be made with maximum parsimony to avoid environmental contamination and also hamper the emergence of resistant strains to biocides used. Objectives: To establish infestation levels of Culex quinquefasciatus based on the insect count adults and their immature forms, collected in big pools and propose tool to estimate the nuisance caused by the bites on the surrounding population. Materials and Methods: The established period collection of mosquito specimens and originated data was from August 2014 to May 2015.For the study area, were chosen two reservoirs of the Municipality of Santo André, São Paulo, Brazil, from the reservoir of the Bom Pastor and the reservoir district, School of Medicine, located in Valparaiso neighborhood. This research proposes the construction of some infestation rates of target species based on two fronts: 1) it was diagnosed by mosquitoes count conducted in the area of big pools. They were counted and identified the adult specimens of this mosquito were collected through aspiration in shelters and aspiration within resting boxes were installed in the areas of big pools and count immature forms (larvae and pupae), collected in aquatic breeding of big pools . 2) Complaints were analyzed stemmed from residents through the Information Service of the City System within a radius corresponding to the boundary area of influence of each reservoir. Results: 1896 adult specimens were collected in the suction activity in shelters, 621 immature specimens and 67 adult specimens aspirated the resting box. Identified the sex of adult specimens and were a predominance of males. From the sampling done in compliance with the natural and anthropogenic variables, and analysis of complaints they were created and applied three indices of infestation (Immature Density per Liter, Mosquitoes Aspirates per Minute Index and Mosquitoes Aspirates from Resting Boxes) and one of complaints (Correspondents Complaints Index). Conclusions: Through the analysis of seasonal aspects, the indexes showed how important tools for control interventions of this pest. The method of resting boxes proved to be unproductive compared to other indices.

Diversas espécies de anuros da família Leptodactylidae se reproduzem em corpos dágua sazonais, temporários e mantidos exclusivamente por chuvas. Em períodos de estiagem prolongada a poça pode secar completamente, ocasionando elevadas taxas de mortalidade de ovos e girinos dessas espécies, podendo exercer forte pressão seletiva na evolução de mecanismos de resistência e sobrevivência nas fases iniciais do desenvolvimento. Algumas espécies de girinos conseguem sobreviver cerca de cinco dias fora dágua o que pode proporcionar uma adaptação vantajosa, porque possibilita a sobrevivência dos girinos por um período que pode ser suficiente para a reincidência de novas chuvas e restabelecimento do corpo dágua. Apesar dessa capacidade de sobrevivência, pouco se sabe sobre as possíveis modificações que a desidratação pode causar na locomoção e na morfologia durante o desenvolvimento desses animais. O presente trabalho teve como objetivo avaliar o efeito do estresse hídrico: (1) no nível de sobrevivência e perda de massa corpórea; (2) no desempenho locomotor; (3) na morfologia externa (morfometria linear) e interna, analisando tanto o volume total quanto o volume visceral (estereologia); e (4) no tempo até metamorfose após o estresse. Utilizamos girinos de duas espécies de anuros, Leptodactylus fuscus (Leptodactylinae) e Physalaemus nattereri (Leiuperinae), ambas as espécies se reproduzem em corpos dágua temporários, em áreas com estação seca definida estando, portanto sujeitas as mesmas pressões seletivas. Além disso, as duas espécies apresentam modos reprodutivos diferentes, podendo apresentar diferentes graus de resistência ao estresse hídrico. Os girinos das duas espécies foram divididos em dois grupos, os que ficaram em água (grupo controle) e os que foram submetidos ao estresse hídrico (grupo tratamento), por três períodos de tempo (12, 24 e 72 horas). Houve diferenças significativas para valores de perda de massa entre os grupos controle e tratamento em ambas as espécies, sendo o grupo tratamento que mais perdeu massa corpórea em todos os períodos, além disso, quase metade dos girinos de P. nattereri morreram em 36 horas de estresse. Não houve diferenças significativas para os dados de desempenho locomotor e volume total entre os grupos testado para girinos de L. fuscus, mas houve diferenças morfometricas significantes nos componentes relacionados a cauda e no volume visceral, onde, o intestino do grupo tratamento foi menor que do controle. Já em P. nattereri, houve diferenças significativas entre os grupos testados para desempenho locomotor, volume total, morfometria da cauda e volume visceral, sendo o estomago e anexo do tratamento maior que do controle. Nossos resultados sugerem que a exposição ao estresse hídrico não afeta significativamente a morfologia e o desempenho locomotor dos girinos de L. fuscus. No entanto, girinos de P. nattereri apresentaram uma sensibilidade ao estresse hídrico prolongado, principalmente sobre o seu desempenho locomotor. / Several species of frogs (Leptodactylidae) breed in temporary pools maintained exclusively by rainfall. These pools easily dry out causing high mortality of eggs or tadpoles thereby possibly exerting strong selective pressure on the evolution of resistance mechanisms and survival in the early stages of development. However, the tadpoles of some species can survive up to five days in pools that are drying out, needing only a humid substrate for development which can provide an advantageous adaptation, because it enables the survival of tadpoles for a period that may be enough for the recurrence of new rains and restoration of the water body. Despite this ability to survive out of water, it is not known which possible damages dehydration stress causes in tadpoles during their ontogeny. The aim of this study was to evaluate the effect of hydric stress on: (1) the level of survival and weight loss; (2) locomotor performance; (3) external (linear morphometry) and internal morphology, analyzing the total volume and visceral volume (stereology); and (4) the time of development after stress. We used tadpoles of two species, Leptodactylus fuscus (Leptodactylinae) and Physalaemus nattereri (Leiuperinae), both species breed in temporary ponds in areas with well-defined dry season therefore these species are subject to the same selective pressure. In addition, the two species show different reproductive modes, and may possess different degrees of resistance to water stress. To this end, the tadpoles were divided into two groups, those who stayed in 100 ml of water (control group) and those that were subjected to hydric stress (treatment group) for three time periods (12, 24 and 72 hours). Significant differences for weight loss were found between the groups (control/treatment) in both species, with the treatment group losing more weight in all stress levels. Furthermore almost half of P. nattereri tadpoles died within 36 hours of stress. There was no significant difference for locomotor performance and total volume between control group and treatment group of L. fuscus tadpoles, but morphometric analyses indicated a significant difference in the components related to tail and visceral volume, with the gut of the treatment group was lower than the control. In P. nattereri tadpoles, there were significant differences between the groups tested for locomotor performance, total volume, tail morphometry and visceral volume, with the stomach of the treatment group being greater than in the control group. Our results suggest that hydric stress has a significant effect on locomotion and morphology of P. nattereri tadpoles, but not in L. fuscus.